Interpenetrating polymer network (IPN) systems use novel polymers that are synthesized by the interlacing of two independent polymers in a cross-linked form. For successful preparation of such IPN systems, at least one of the participating polymers should be synthesized/cross-linked in the immediate presence of the other. The polymers used to fabricate an IPN system are independently cross-linked or cross-linked to each other. They can be prepared by selective combination of the starting polymers to tailor the final product based on the ultimately desired characteristics. The nontoxic nature and biodegradability of natural polymers can thus be combined with the robustness and strength offered by the synthetic polymers by fabricating their IPN systems. The present review aims to summarize the IPN systems in terms of their advantages, disadvantages, and different drug delivery systems based on these polymers and their numerous biomedical applications. This review includes a detailed study of the recent publications and patents describing the use of IPNs in different spheres/formulations.